1. Field of the Invention
The invention relates to a method in processing gypsum boards or tiles to be mounted on a framework in wall constructions or as a lining in ceilings and on walls, including gypsum boards or tiles consisting of a gypsum core with a protective and binding layer of paper on each side thereof, and gypsum boards and tiles consisting of a mixture of gypsum and fibre material, or more generally any board or tile including gypsum as an essential constituent thereof. In the following the term xe2x80x9cboardxe2x80x9d will be used as including gypsum boards as well as gypsum tiles
More particularly the invention relates to the processing of gypsum board of any kind mentioned above perforated e.g. by circular or square apertures or by slots arranged on the gypsum board in different patterns, the perforation being formed e.g. by punching or sawing. Such perforated gypsum boards often are provided at one side thereof with a woven or felted textile material, which in combination with the apertures or slots improves the sound absorbing properties of the gypsum board. The gypsum board may be varnished in order to improve the appearance thereof.
2. Description of Related Art
Perforation of the gypsum board creates uncovered shear surfaces in the apertures or slots, from which gypsum particles are detached, such particles being emitted to the surroundings as dust when the gypsum boards are shipped or mounted or are being used. The emission of such dust is felt as a problem when handling perforated gypsum boards during storing, distribution and use thereof. Brushing of the gypsum boards in order to remove the gypsum dust therefrom has been found not to be sufficient in order to avoid the problem of dusting. Moreover, gypsum dust covering the surfaces of the gypsum board causes difficulties when the boards are to be painted since the dust prevents the paint from adhering to the board surfaces.
The object of the present invention is to eliminate the problem by processing steps which easily can be incorporated in an automatic continuous production line without changes in the production method being necessary.
According to the invention said object is achieved by the method of claim 1. By this method the dust can effectively be removed from the gypsum boards without causing damages to the boards. Since small amounts of water can be used for an efficient cleaning of the boards and water is blown and/or sucked off the boards the consumption of energy for drying the boards when they have been sprayed with water can be held at an acceptable low level.